/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.validation;

import org.springframework.beans.PropertyAccessException;
import org.springframework.context.support.DefaultMessageSourceResolvable;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;

/**
 * Default {@link BindingErrorProcessor} implementation.
 *
 * <p>Uses the "required" error code and the field name to resolve message codes
 * for a missing field error.
 *
 * <p>Creates a {@code FieldError} for each {@code PropertyAccessException}
 * given, using the {@code PropertyAccessException}'s error code ("typeMismatch",
 * "methodInvocation") for resolving message codes.
 *
 * @author Alef Arendsen
 * @author Juergen Hoeller
 * @see #MISSING_FIELD_ERROR_CODE
 * @see DataBinder#setBindingErrorProcessor
 * @see BeanPropertyBindingResult#addError
 * @see BeanPropertyBindingResult#resolveMessageCodes
 * @see org.springframework.beans.PropertyAccessException#getErrorCode
 * @see org.springframework.beans.TypeMismatchException#ERROR_CODE
 * @see org.springframework.beans.MethodInvocationException#ERROR_CODE
 * @since 1.2
 */
public class DefaultBindingErrorProcessor implements BindingErrorProcessor {

    /**
     * Error code that a missing field error (i.e. a required field not
     * found in the list of property values) will be registered with:
     * "required".
     */
    public static final String MISSING_FIELD_ERROR_CODE = "required";


    @Override
    public void processMissingFieldError(String missingField, BindingResult bindingResult) {
        // Create field error with code "required".
        String fixedField = bindingResult.getNestedPath() + missingField;
        String[] codes = bindingResult.resolveMessageCodes(MISSING_FIELD_ERROR_CODE, missingField);
        Object[] arguments = getArgumentsForBindError(bindingResult.getObjectName(), fixedField);
        FieldError error = new FieldError(bindingResult.getObjectName(), fixedField, "", true,
                codes, arguments, "Field '" + fixedField + "' is required");
        bindingResult.addError(error);
    }

    @Override
    public void processPropertyAccessException(PropertyAccessException ex, BindingResult bindingResult) {
        // Create field error with the exceptions's code, e.g. "typeMismatch".
        String field = ex.getPropertyName();
        Assert.state(field != null, "No field in exception");
        String[] codes = bindingResult.resolveMessageCodes(ex.getErrorCode(), field);
        Object[] arguments = getArgumentsForBindError(bindingResult.getObjectName(), field);
        Object rejectedValue = ex.getValue();
        if (ObjectUtils.isArray(rejectedValue)) {
            rejectedValue = StringUtils.arrayToCommaDelimitedString(ObjectUtils.toObjectArray(rejectedValue));
        }
        FieldError error = new FieldError(bindingResult.getObjectName(), field, rejectedValue, true,
                codes, arguments, ex.getLocalizedMessage());
        error.wrap(ex);
        bindingResult.addError(error);
    }

    /**
     * Return FieldError arguments for a binding error on the given field.
     * Invoked for each missing required field and each type mismatch.
     * <p>The default implementation returns a single argument indicating the field name
     * (of type DefaultMessageSourceResolvable, with "objectName.field" and "field" as codes).
     *
     * @param objectName the name of the target object
     * @param field      the field that caused the binding error
     * @return the Object array that represents the FieldError arguments
     * @see org.springframework.validation.FieldError#getArguments
     * @see org.springframework.context.support.DefaultMessageSourceResolvable
     */
    protected Object[] getArgumentsForBindError(String objectName, String field) {
        String[] codes = new String[]{objectName + Errors.NESTED_PATH_SEPARATOR + field, field};
        return new Object[]{new DefaultMessageSourceResolvable(codes, field)};
    }

}
